In summary, Liu et al. realized the thermally-induced spin transition with colossal PTE and NTE properties in a cyano-bridged hexanuclear complex. The spin transition as well as the conformational {Fe^III₂Fe^II₂} unit and modifications in intermolecular C–H⋅⋅⋅π interactions, ultimately resulting in NTE along the b axis. This work demonstrates that merging SCO compounds with a pliable rhombic structure and intermolecular interactions leads to exceptional structural and thermodynamic characteristics. This approach represents a significant strategy in the realm of crystal engineering and thermo-responsive molecular devices.